1. Field of the Invention
The present invention generally relates to telescopes used with firearms. More specifically, this invention relates to a variable power telescope which is electrically adjustable so as to permit the shooter to selectively increase and decrease the magnification of the telescope without requiring the shooter to alter his or her grip on the firearm.
2. Description of the Prior Art
Telescopes are often attached to firearms, most often hunting and target rifles, to improve the accuracy of the user's aim. Variable power telescopes with "zoom" capability are also known, and permit the user to adjust the magnification of the target to suit the particular needs of the user and the occasion. For example, as the distance between the target and the user increases, it is generally desirable to increase the magnification power of the telescope. In addition, when the type of background behind the target makes initially sighting the target difficult, the user will often decrease the magnification to increase the field of vision through the telescope. Once the target is in view, the telescope can be zoomed to magnify the image of the target to a suitable level.
A conventional optical system for a telescope generally includes a pair of lenses which alter the magnification of the image seen by the user as the lenses are moved relative to each other along an axis corresponding to the user's line of sight through the telescope. Adjustment of the telescope's magnification is made with an adjustment ring or wheel located near the rear of the telescope. The adjustment ring typically controls an adjustment mechanism which includes a camming feature that, when rotated, causes the rear lens to move toward or away from the front lens, so as to increase or decrease the magnification of the target image.
While such variable powered telescopes are widely used, they have a significant drawback in that it is rather inconvenient to rotate the adjustment ring to adjust the magnification of the telescope. Generally, the user must take one hand from the gun in order to adjust the magnification. To do this safely, the user must typically lower the firearm, rotate the adjustment ring, and then again raise the firearm to locate the target through the telescope. In doing so, the user will have lost sight of the target, and consequently must again find the target under increased magnification which, as noted before, is more difficult in that the telescope now provides a smaller field of vision. If the user attempts to maintain the firearm on its target during adjustment, he or she is confronted with holding a firearm often weighing ten pounds or more with only one hand while turning the adjustment ring with the other. Not only is such a maneuver difficult, particularly when trying to keep sight of the target, but it can also be quite dangerous.
Accordingly, what is needed is a device which can be mounted to a telescope for providing an adjustment capability which alleviates the need for the user to support the firearm with one hand while making the adjustment, while also permitting the user to maintain his or her sight through the telescope on the target while the adjustment is made.